Ink composition, inkjet recording method, and printed article

Abstract

The present invention provides an ink composition having excellent ink ejection stability and stretching property, curable with a high sensitivity by irradiation of radiation rays, and capable of forming an image excellent in rubfastness and blocking resistance, an inkjet recording method using the ink composition, and a printed article. The ink composition includes (a) a polymer having a siloxane structure and a polymerizable group on a side chain thereof, (b) a polymerizable compound, and (c) a photopolymerization initiator, and the inkjet recording method includes a step of ejecting the ink composition onto a recording medium to be recorded with an inkjet recording apparatus and a step of curing the ink composition by irradiating active radiation rays on the ejected ink composition.

1. An ink composition comprising: (a) a polymer having a siloxane structure and a polymerizable group on a side chain thereof; (b) a polymerizable compound; (c) a photopolymerization initiator; and (d) a monofunctional monomer, the siloxane structure being obtained by polymerizing a compound represented by the following Formula (A): 
       
         
           
           
               
               
           
         
         wherein in Formula (A), R 1  is a straight chain or branched alkylene group having 2 to 6 carbon atoms or a divalent connecting group represented by the following Formula (B); x 1 , x 2  and x 3  are integers having a relationship such that the sum of x 1 , x 2  and x 3 , (x 1 +x 2 +x 3 ), is from 1 to 100; y 1  is an integer of from 1 to 10; X is a single bond or a divalent group represented by the following Formula (C); Y represents a monovalent group represented by any of Formulae (D) to (F); and Z represents a monovalent group represented by the following Formula (G); 
       
       
         
           
           
               
               
           
         
         wherein in Formula (B), R 2  represents a hydrogen atom or a methyl group, and n represents an integer of from 1 to 50;
   —Z 1 —CO—NH—R 3 —NH—CO—  Formula (C)
 
 
         wherein in Formula (C), Z 1  represents an oxygen atom, a sulfur atom, or NR 4 ; R 4  represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Z 1  is bonded to R 1  in Formula (A); and R 3  represents a divalent aliphatic or alicyclic group having 6 to 10 carbon atoms; 
       
       
         
           
           
               
               
           
         
         wherein in Formulae (D) to (F), R 5  represents a hydrogen atom or a straight chain or branched alkyl group having 1 to 6 carbon atoms, R 6  represents a straight chain or branched alkylene group having 2 to 10 carbon atoms, and R 7  represents a straight chain or branched alkylene group having 1 to 6 carbon atoms; 
       
       
         
           
           
               
               
           
         
         wherein in Formula (G), z 1  is an integer of from 3 to 100, and 
         wherein the content of the polymer (a) is, with respect to the total solid content of the ink composition, from 0.1% to 10% by mass. 
       
     
     
       2. The ink composition according to  claim 1 , wherein the polymerizable group of the polymer (a) on a side chain thereof is a radical polymerizable group. 
     
     
       3. The ink composition according to  claim 1 , wherein the polymerizable group of the polymer (a) on a side chain thereof is a cationic polymerizable group. 
     
     
       4. The ink composition according to  claim 1 , wherein the polymer (a) further comprises a monomer capable of forming a homopolymer having a glass transition temperature of 50° C. or higher as a copolymerized component, wherein the monomer capable of forming a homopolymer having a glass transition temperature of 50° C. or higher is at least one selected from the group consisting of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butyl (meth)acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenethyl (meth)acrylate, methyl 2-chloro(meth)acrylate, ethyl α-chloroacrylate, (meth)acrylamide, N-isopropyl acrylamide, and dicylopentanyl (meth)acrylate. 
     
     
       5. The ink composition according to  claim 1 , wherein the polymerizable compound (b) is a radical polymerizable compound. 
     
     
       6. The ink composition according to  claim 1 , wherein the polymerizable compound (b) is a cationic polymerizable compound. 
     
     
       7. An inkjet recording composition comprising the ink composition of  claim 1 . 
     
     
       8. An inkjet recording method comprising:
 ejecting on a recordable medium the ink composition of  claim 1  using an inkjet recording apparatus; and 
 curing the ink composition by irradiation of an actinic radiation ray to the ejected ink composition. 
 
     
     
       9. A printed article recorded by the inkjet recording method according to  claim 8 . 
     
     
       10. The ink composition according to  claim 1 , wherein the monofunctional monomer (d) is N-vinyl caprolactam.